Brake



u y 1940. o. H. FOWLER 2,206,604

BRAKE Filed Aug. 20. 1957 /z sow 52\ 54 [i j M INVENTOR 7' Z 5 Z, OWEN/7. Fan z. :2

BY M

ATTORNEY '5 two braking shoes so that the braking obtained ing a rim to which is suitably secured a lining Patented July 2, 1 i I UNITED STATES PATENT OFFICE BRAKE Gwen H. Fowler, Detroit, Micln, assignor to Hydraulic Brake- Company, Detroit, Mlcln, a corporation of California Application August 20. 1937, Serial No. 160,184

1 Claims. (01.188-152) This invention relates to brakes, and more paron the backing plate are a p ir of r p n ticularly to internal expanding brakes. ing interchangeable friction elements or shoes i4 I In the conventional internal expanding brake, and I8 adaptable for cooperation with the drum. wherein the applied force is distributed between Each of the shoes includes a web It supportis the sum of the friction on the two shoes, the 22. The articulate ends of the shoes are pivoted forward braking shoe is more effective than the on diametrically disposed anchors 24 and 26 trailing or reverse braking shoe. This is due to rr nged on the backing p n b e r the wiping action of the drum causing self-actutractile stops 2B and 30. also arranged on the ation of the forward braking shoe and tending backing plate. serve to support the shoes in m to repel the trailing brake shoe. proper spaced relation to the drum when the The present invention comprehends the utilizabrake is at rest. Retrop ngs 32 and 34. tion of this self-actuating feature by arranging nn cting the r sp ti s s d a nt th r the brake shoes in tandem, thatis, with the toe of m'ce app y e d to fi d pports 36 and 33 one of the brake shoes adjacent the heel of the arranged on the backing plate. serve to return other braking shoe so that the applied force and retain the shoes on the stops 28 and 30 upon when distributed between the shoes may be aug pletion of a braking operation. mented by the self-actuation of the shoes. This An equalizer 40 preferably includes spaced is particularly desirable in brakes for airplanes. plates 42 and M connected as by a web 48 having 20 wherein reverse braking is non-essential. a centralized depression 48. The plates are 29 An object of the invention is to provide braking I transversely bored to provide corresponding structure wherein maximum efficiency may be spaced registering openings arranged equi-disattained. tant from the depression 48 in the web 4%. These Another object of the invention is to provide openings receive suitable pivot pins 50 and 52 braking structure wherein the friction elements secured against displacement as at 54, and the 25 may be applied with equal force and elect. force applying end of the shoes it is pivotaliy Another object of the invention is to provide connected to the pivot pin 50. a braking structure including two friction ele- A lever 58 slidably supported on the web it ments, both operative as forward braking eleand the shoe preferably includes a strip of 30 ments. metal bent upon itself to provide a channel 5d 30 A further object of the invention is to provide and so deformed as to correspond to the curvameans for simultaneously applying equal operture of the inner perimeter of the web. The ating force to brake shoes mounted on diametrichannel I0 receives the web with small clearance rally disposed pivots. so as to provide for free relative movement be- Yet a further object of the invention is to protween the shoes and the lever, and to eliminate 35 vide-a brake structure havingbirt few component chatter and other objectionable noises. One parts of simple structure so that its manufacture end of the lever 58 is connected to the pivot pin may be economically facilitated both as to parts I2 01' the equalizer 40, and the other end of the and asembly. lever is pivotally connected to the force apply- 40 other objects and features of the invention ing end of the shoe i8 as indicated at til. 40..

will appear from the following description taken Means for actuating the shoe include a fluid in connection with-the drawing forming a part pressure producing device of conventional type or this specification, and in whichnot shown, and a fluid pressure actuated motor. Fig. 1 is a sectional view'of a brake taken just also of conventional type, operatively connected back of the head of the drum illustrating the to the fluid pressure producing device. The mo- 45 invention as applied; tor includes a cylinder 82 suitably mounted on Fig; 2 is a vertical sectional view substantially the backing plate, a piston 64 movable in the cylon line 2-2, Fig. 1; and inder. and a thrust pin 88 having one end seated Fig. 3 is a sectional view substantially on line in a r cess in th back of the piston and it 8-4, Fig. 1. 14 other end seated inthe recess 48 of the equal- 50 Referring to the drawing for more specific izer 40. details of the invention, Ill represents a fixed In operation, upon actuation of the fluid pressupport or backing plate having associated theresure producing device, fluid under pressure is with a rotatable drum II, which may be secured received in the fluid pressure actuated motor, as to a wheel, not shown. Positioned for movement resulting in movement of the piston 64 on its 55,

compression stroke, and this movement of the piston is transmitted through the thrust pin 65 to the equalizer 30. This equalizer functions to distribute the force thus produced equally between the shoe M and the lever 56. This causes actuation of the shoe it into engagement with the drum 02 against the resistance of the retractile spring 32, and at the same time the force exerted on the lever 56 is transmitted through the lever, slidable on the web It of the shoe M, to the shoe 86, resulting in actuation of the shoe into engagement with the drum against the resistance of the retractile spring 36. Thus both shoes are actuated as forward braking shoes. Hence the applied force is augmented by the actuation of the shoes.

Upon conclusion of a braking operation, the applied force is released, and the fluid in the fluid pressure actuated motors is returned to the fluid pressure producing device under the influence of the retractile springs 36 and 36 as the shoes move to their retracted or off position against the stops 28 and 30, and during this movement of the shoes the lever 58 slides on the web it of the shoe Hi to its position of rest.

Although this invention has been described in connection with certain specific embodiments, the principles involved are susceptible of numerous other applications that will readily occur to persons skilled in the art. The invention is, therefore, to be limited only by the scope of the appended claims.

Having thus described the various features of the invention, what I claim as new and desire to secure by Letters Patent is:

l. A brake comprising a fixed support, a pair of shoes pivoted on the support in tandem, and means slidably supported on one of the shoes and connected to the force applying ends of the shoes for actuating the shoes simultaneously and with equal effectiveness.

2. A brake comprising a fixed support, a pair of shoes mounted thereon in tandem, a lever slidable on one of the shoes and connected to the other shoe, an equalizer connected between the lever and the shoe supporting the lever, and means for applying force to the equalizer.

3. A brake comprising a fixed support, a pair of shoes mounted thereon in tandem, a lever pivotally connected to one of the shoes and slidable on the other shoe. an equalizer connected to the lever and to the shoe supporting the lever, and a force applying means operatively connected to the equalizer.

4. A brake comprising a fixed support, a drum associated therewith, shoes pivoted on the support in tandem for cooperation with the drum, an equalizing mechanism connected between the diametrically disposed force applying ends of the shoes including a lever slidable on one or the shoes, and means for applying force to the equalizer.

5. A'brake comprising a fixed support, a drum associated therewith, a pair of shoes mounted in tandem on the support for cooperation with the drum, a lever slidably supported on one of the shoes and connected to the force applying end of one of the shoes, an equalizer connecting the lever to the force applying end of the shoe supporting the lever, and a motor operatively connected to the equalizer.

6- A brake comprising a pair of shoes arranged in tandem, a lever pivotally connected to one of the shoes and slidably embracing the other shoe, an equalizer connected between the lever and the shoe embraced by the lever, and a fluid pressure 

